Round-tailed Ground Squirrel

The round-tailed ground squirrel is found in desert regions of California from the Mexican
border to southern Inyo Co. Optimum habitats are
desert succulent shrub,
desert wash,
desert scrub,
alkali desert scrub,
and levees in cropland habitat. Also found in urban habitat.
Found from -60 to 900m (-180 to 2900 ft) elevation.

SPECIFIC HABITAT REQUIREMENTS

Feeding: Prefers seeds, leaves,
flowers,
and other plant parts of grasses, forbs, and
shrubs. Green vegetation is in the diet in all months of the year. Will also take insects and
spiders. Feeds on the ground surface and climbs in shrubs and trees.

Cover: Burrows at the base of shrubs. Uses levees in agricultural habitats.

Reproduction: Nests are constructed in burrows.

Water: Probably does not require water.

Pattern: Prefers open, flat, grassy areas in fine-textured, sandy soil. A mixture of shrub
species is preferred; habitats dominated by creosote bush had fewer squirrels than those
without it (Dunford 1977). Prefers sandy soil for hibernation. Density is correlated with winter
rainfall. Tends to occur in disjunct populations (Ernest and Mares 1987).

SPECIES LIFE HISTORY

Activity Patterns:
Diurnal;
hibernates from late August or early September to January or
February (Neal 1965b, Dunford 1977). Activity is bimodal in summer, peaking early and late
in day, and unimodal in fall and spring, peaking at midday. More active after rain.

Seasonal Movements/Migration: None.

Home Range: Adult home ranges averaged 0.74 ha (1.85 ac) regardless of sex or age.
Home range may shift to include preferred foods, but home ranges remain relatively stable for
2, or more, years. Densities varied from 25-225 per ha (10-100 per ac), and are highest when
juveniles emerge.

Territory: Adults are territorial, beginning in March. Juveniles become territorial in July or
August. At high densities, many individuals may be wounded in territorial disputes.

Reproduction: Mating takes place during late February to March. After a gestation of
27-35 days, the young are born during mid-March to April. The single litter of altricial young
averages 6.5 (range 1 -12). Lactation takes place in April to May, and the young are weaned
after about 35 days. The young emerge in May, and most males disperse in June. First
reproduction takes place in yearlings. Above average winter rain increases the litter size, and
additional rains in December and January advance the breeding season (Reynolds and
Turkowski 1972).

Niche:
Gopher snakes,
prairie falcons,
and house cats are major predators (Dunford
1977). The range of the round-tailed ground squirrel abuts that of the similar
Mohave ground squirrel.

Comments: Populations of S. t. chlorus are restricted to the Coachella Valley, Riverside
Co., and are reduced by urbanization, cultivation, and development.

The round-tailed ground squirrel usually lives in burrows within
creosote bush scrub
habitat.
Their color may vary from light brown to a dark reddish-brown.
They eat seeds, cacti and the green parts of shrubs and other plants.
It is diurnal, and will remain underground during the hottest parts of the days in summer.